From July 1, more New Zealanders will get free doctors' visits, vehicle licensing will become cheaper, and paid parental leave payments will increase.
Funding will also increase for palliative care, which will allow hospices to expand their services for terminally ill people.
As promised in last year's budget, GP visits and prescriptions will be free for under-13-year-olds from tomorrow.
Mr Key said the change was possible because of careful management of the government's books. It was expected to benefit 400,000 children at a cost of around $30 million a year.
Beginning tomorrow, the maximum weekly rate for paid parental leave will increase from $504.10 to $516.85. The increase reflected the 2.5 per cent rise in the average weekly wage over the last year.
In April, paid parental leave was extended from 14 weeks to 16 weeks, though Opposition parties wanted it to be raised to 26 weeks.
National's election promise to increase funding for palliative care will kick off tomorrow, with $13 million more in funding for the country's 29 hospices.
The funding boost was designed to allow the hospices to keep pace with an ageing population.
Labour's health spokeswoman Annette King said she supported any funding boost in areas of need, but it came after cuts in spending on hospice care.
She said that under the Labour Government, hospices were 70 per cent Government-funded.
"Over the seven years of the National Government, they slowly let it fade away again to 50 per cent. This funding takes back it to 70 per cent, so you've actually got the status quo."
The average ACC motor vehicle levy will fall tomorrow from around $330 to $195 a year.
ACC Minister Nikki Kaye announced the change in February, saying it would return around $438 million to levy payers.
Other changes include an increase in support for solo parents who are studying.
